MEXICO CITY — Authorities say a man who joined Mexico's growing civilian anti-crime protest movement after his son disappeared has been shot to death in his hometown in the northern state of Sonora.

Nepomuceno Moreno repeatedly had accused police in the Sonoran capital of Hermosillo of kidnapping his 18-year-old son last year. The 56-year-old father became a vocal member of poet Javier Sicilia's Movement for Peace with Justice and Dignity, which has held marches and rallies denouncing drug traffickers, street criminals and the Mexican government's military-led offensive against crime.

The state prosecutor's office said Moreno was shot to death Monday as he drove in his van.

Moreno said before his death that he had received repeated threats from the men he believed responsible for kidnapping his son.